THE ATTENUATION OF BLUE-ON-YELLOW PERIMETRY BY THE MACULAR PIGMENT

Purpose: To determine the influence of macular pigment absorption on b lue-on-yellow perimetry using a technique suitable for application wit h the Humphrey Field Analyzer. Methods The sample comprised one eye fr om each of 46 healthy subjects (age range, 20-80 years). Macular pigme nt absorption was assessed by measuring medium-wavelength sensitive co ne sensitivity for 460- and 570-nm narrowband stimuli at the fovea, at 5.5 degrees and at 8 degrees eccentricity. The differences in sensiti vities recorded between the fovea and 8 degrees eccentricity and betwe en 5.5 degrees and 8 degrees eccentricity for the 460-nm stimulus rela tive to a value of zero at 570 nm were attributed to absorption by the macular pigment. Blue-on-yellow perimetry was undertaken using a 460- nm narrowband blue Goldmann size V stimulus and a yellow 330-cdm(-2) b ackground. Results: Group macular pigment absorption (mean +/- standar d error) was 0.40 +/- 0.03 log units foveally and 0.00 +/- 0.03 log un its at 5.5 degrees eccentricity. The group mean foveal macular pigment absorption was significantly different from zero (P ( 0.01). The coef ficient of repeatability for the macular pigment absorption procedure (based on test-retest data for 16 subjects) was +/- 0.28 log units at the fovea and +/- 0.35 log units at 5.5 degrees eccentricity. Conclusi on: The net effect of ocular media and macular pigment absorption rela tive to 460 nm was to attenuate the blue-on-yellow visual field at the fovea by approximately 0.80 log units and elsewhere by 0.40 log units .